Clean up mapRectToPaintInvalidation backing to not take an unnecessary fixed-position argument
except in the case of RenderView, which is the only class that needs to care.

BUG=402983

Review URL: https://codereview.chromium.org/502723003

git-svn-id: svn://svn.chromium.org/blink/trunk@180876 bbb929c8-8fbe-4397-9dbb-9b2b20218538